1. Field of the Invention
The present invention relates to devices for handling cards, including cards known as “playing cards.” In particular, it relates to an electromechanical machine for continuously shuffling playing cards, whereby a dealer has a substantially continuously readily available supply of shuffled cards for dealing and where cards may be monitored for security purposes during play of the game.
2. Background of the Art
Wagering games based on the outcome of randomly generated or selected symbols are well known. Such games are widely played in gaming establishments and include card games wherein the symbols comprise familiar, common or standard playing cards. Card games such as twenty-one or blackjack, poker, poker variations, match card games and the like are excellent casino card games. Desirable attributes of casino card games are that they are exciting, that they can be learned and understood easily by players, and that they move or are played rapidly to their wager-resolving outcome.
From the perspective of players, the time the dealer must spend in shuffling diminishes the excitement of the game. From the perspective of casinos, shuffling time reduces the number of wagers placed and resolved in a given amount of time, thereby reducing revenue. Casinos would like to maximize the amount of revenue generated by a game without changing games, without making obvious changes that indicate an increased hold by the house, particularly in a popular game, and without increasing the minimum size of wagers. One approach to maximizing revenue is speeding play. It is widely known that playing time is diminished by shuffling and dealing. This approach has lead to the development of electromechanical or mechanical card shuffling devices. Such devices increase the speed of shuffling and dealing, reduce non-play time, thereby increasing the proportion of playing time to non-playing time, adding to the excitement of a game by reducing the time the dealer or house has to spend in preparing to play the game.
U.S. Pat. No. 4,515,367 (Howard) is an example of a batch-type shuffler. The Howard patent discloses a card mixer for randomly interleaving cards including a carriage supported ejector for ejecting a group of cards (approximately two playing decks in number) which may then be removed manually from the shuffler or dropped automatically into a chute for delivery to a typical dealing shoe.
U.S. Pat. No. 5,275,411 (Breeding) discloses a machine for automatically shuffling a single deck of cards including a deck receiving zone, a carriage section for separating a deck into two deck portions, a sloped mechanism positioned between adjacent corners of the deck portions, and an apparatus for snapping the cards over the sloped mechanism to interleave the cards.
U.S. Pat. 3,897,954 (Erickson et al.) discloses the concept of delivering cards one at a time, into one of a number vertically stacked card shuffling compartments. The Erickson patent also discloses using a logic circuit to determine the sequence for determining the delivery location of a card, and that a card shuffler can be used to deal stacks of shuffled cards to a player. U.S. Pat. 5,240,140 (Huen) discloses a card dispenser which dispenses or deals cards in four discrete directions onto a playing surface, and U.S. Pat. No. 793,489 (Williams), U.S. Pat. No. 2,001,918 (Nevius) U.S. Pat. No. 2,043,343 (Warner) and U.S. Pat. No. 3,312,473 (Friedman et al.) disclose various card holders some of which include recesses (e.g., Friedman et al.) to facilitate removal of cards. U.S. Pat. No. 2,950,005 (MacDonald) and U.S. Pat. No. 3,690,670 (Cassady et al.) disclose card sorting devices which require specially marked cards, clearly undesirable for gaming and casino play.
U.S. Pat. Nos. 5,584,483 and 5,676,372 (Sines et al.) describe batch type shufflers which include a holder for an unshuffled stack of cards, a container for receiving shuffled cards, a plurality of channels to guide the cards from the unshuffled stack into the container for receiving shuffled cards, and an ejector mounted adjacent to the unshuffled stack for reciprocating movement along the unshuffled stack. The position of the ejector is randomly selected. The ejector propels a plurality of cards simultaneously from a number of points along the unshuffled stack, through the channels, and into the container. A shuffled stack of cards is made available to the dealer.
U.S. Pat. No. 5,695,189 (Breeding et al.) is directed to a shuffling machine for shuffling multiple decks of cards with three magazines wherein unshuffled cards are cut then shuffled.
Aside from increasing speed and playing time, some shuffler designs have provided added protection to casinos. For example, one of the Breeding (similar to that described in U.S. Pat. No. 5,275,411) shufflers is capable of verifying that the total number of cards in the deck has not changed. If the wrong number of cards are counted, the dealer can call a misdeal and return bets to players.
A number of shufflers have been developed which provide a continuous supply of shuffled cards to a player. This is in contrast to batch type shuffler designs of the type described above. The continuous shuffling feature not only speeds the game, but protects casinos against players who may achieve higher than normal winnings by counting cards or attempting to detect repeated patterns in cards from deficiencies of randomization in single batch shufflers. An example of a card game in which a card counter may significantly increase the odds of winning by card counting or detecting previously occurring patterns or collections of cards is Blackjack.
U.S. Pat. No. 4,586,712 (Lorber et al.) discloses a continuous automatic shuffling apparatus designed to intermix multiple decks of cards under the programmed control of a computer. The Lorber et al. apparatus is a carousel-type shuffler having a container, a storage device for storing shuffled playing cards, a removing device and an inserting device for intermixing the playing cards in the container, a dealing shoe and supplying means for supplying the shuffled playing cards from the storage device to the dealing shoe. The Lorber shuffler counts the number of cards in the storage device prior to assigning cards to be fed to a particular location.
The Samsel, Jr. patent (U.S. Pat. No. 4,513,969) discloses a card shuffler having a housing with two wells for receiving stacks of cards. A first extractor selects, removes and intermixes the bottommost card from each stack and delivers the intermixed cards to a storage compartment. A second extractor sequentially removes the bottommost card from the storage compartment and delivers it to a typical shoe from which the dealer may take it for presentation to the players.
U.S. Pat. No. 5,382,024 (Blaha) discloses a continuous shuffler having a unshuffled card receiver and a shuffled card receiver adjacent to and mounted for relative motion with respect to the unshuffled card receiver. Cards are driven from the unshuffled card receiver and are driven into the shuffled card receiver forming a continuous supply of shuffled cards. However, the Blaha shuffler requires specially adapted cards, particularly, plastic cards, and many casinos have demonstrated a reluctance to use such cards.
U.S. Pat. No. 5,000,453 (Stevens et al.) discloses an apparatus for automatically and continuously shuffling cards. The Stevens et al. machine includes three contiguous magazines with an elevatable platform in the center magazine only. Unshuffled cards are placed in the center magazine and the spitting rollers at the top of the magazine spit the cards randomly to the left and right magazines in a simultaneous cutting and shuffling step. The cards are moved back into the center magazine by direct lateral movement of each shuffled stack, placing one stack on top of the other to stack all cards in a shuffled stack in the center magazine. The order of the cards in each stack does not change in moving from the right and left magazines into the center magazine.
U.S. Pat. No. 4,770,421 (Hoffman) discloses a continuous card-shuffling device including a card loading station with a conveyor belt. The belt moves the lowermost card in a stack onto a distribution elevator whereby a stack of cards is accumulated on the distribution elevator. Adjacent to the elevator is a vertical stack of mixing pockets. A microprocessor preprogrammed with a fixed number of distribution schedules is provided for distributing cards into a number of pockets. The microprocessor sends a sequence of signals to the elevator corresponding to heights called out in the schedule. Single cards are moved into the respective pocket at that height. The distribution schedule is either randomly selected or schedules are executed in sequence. When the cards have been through a single distribution cycle, the cards are removed a stack at a time and loaded into a second elevator. The second elevator delivers cards to an output reservoir. Thus, the Hoffman patent requires a two step shuffle, i.e., a program is required to select the order in which stacks are moved onto the second elevator. The Hoffman patent does not disclose randomly selecting a pocket for delivering each card. Nor does the patent disclose a single stage process which randomly arranges cards into a degree of randomness satisfactory to casinos and players. Although the Hoffman shuffler was commercialized, it never achieved a high degree of acceptance in the industry. Card counters could successfully count cards shuffled in the device, and it was determined that the shuffling of the cards was not sufficiently random.
U.S. Pat. No. 5,683,085 (Johnson) describes a continuous shuffler which includes a chamber for supporting a main stack of cards, a loading station for holding a secondary stack of cards, a stack gripping separating mechanism for separating or cutting cards in the main stack to create a space and a mechanism for moving cards from the secondary stack into the spaces created in the main stack.
U.S. Pat. No. 4,659,082 (Greenberg) discloses a carousel type card dispenser including a rotary carousel with a plurality of card compartments around its periphery. Cards are injected into the compartments from an input hopper and ejected from the carousel into an output hopper. The rotation of the carousel is produced by a stepper motor with each step being equivalent to a compartment. In use, the carousel is rotated past n slots before stopping at the slot from which a card is to be ejected. The number n is determined in a random or near random fashion by a logic circuit. There are 216 compartments to provide for four decks and eight empty compartments when all the cards are inserted into compartments. An arrangement of card edge grasping drive wheels are used to load and unload the compartments.
U.S. Pat. No. 5,356,145 (Verschoor) discloses another card shuffler involving a carousel or “rotatable plateau.” The Verschoor shuffler has a feed compartment and two card shuffling compartments which each can be placed in first and second positions by virtue of a rotatable plateau on which the shuffling compartments are mounted. In use, once the two compartments are filled, a drive roller above one of the shuffling compartments is actuated to feed cards to the other compartment or to a discharge means. An algorithm determines which card is supplied to the other compartment and which is fed to the discharge. The shuffler is continuous in the sense that each time a card is fed to the discharge means, another card is moved from the feed compartment to one of the shuffling compartments.
U.S. Pat. No. 4,969,648 (Hollinger et al.) discloses an automatic card shuffler of the type that randomly extracts cards from two or more storage wells. The shuffler relies on a system of solenoids, wheels and belts to move cards. Cards are selected from one of the two wells on a random basis so a deck of intermixed cards from the two wells is provided in a reservoir for the dealer. The patent is principally directed to a method and apparatus for detecting malfunctions in the shuffler, which at least tends to indicate that the Hollinger et al. shuffler may have some inherent deficiencies, such as misalignments of extraction mechanisms.
The size of the buffer supply of shuffled cards in the known continuous shufflers is large, i.e., 40 or more cards in the case of the Blaha shuffler. The cards in the buffer cannot include cards returned to the shuffler from the previous hand. This undesirably gives the player some information about the next round.
Randomness is determined in part by the recurrance rate of a card previously played in the next consecutively dealt hand. The theoretical recurrence rate for known continuous shufflers is believed to be about zero percent. A completely random shuffle would yield a 13.5% recurrance rate using four decks of cards.
Although the devices disclosed in the preceding patents, particularly the Breeding machines, provide improvements in card shuffling devices, none describes a device and method for providing a continuous supply of shuffled cards with the degree of randomness and reliability required by casinos until the filing of copending U.S. patent application Ser. No. 09/060,598, now U.S. Pat. No. 6,254,096, issued Jul. 3, 2001. That device and method continuously shuffles and delivers cards with an improved recurrence rate and improves the acceptance of card shufflers and facilitate the casino play of card games.